Abnormal shock index exposure and clinical outcomes among critically ill patients: A retrospective cohort analysis

Development of modified laser Doppler flowmetry device for real-time monitoring of esophageal mucosal blood flow: a preclinical assessment with an animal model

This study aimed to modify a laser Doppler flowmeter designed and assembled at our institute. After measuring sensitivity evaluation in ex vivo experiments, we confirmed the efficacy of this new device for monitoring real-time esophageal mucosal blood flow changes after thoracic stent graft implantation by simulating various clinical situations in an animal model. Thoracic stent graft implantation was performed in a swine model (n = 8). Esophageal mucosal blood flow decreased significantly from baseline (34.1 ± 18.8 ml/min/100 g vs. 16.7 ± 6.6 ml/min/100 g, P < 0.05) in the lower esophagus (Th6-Th8) where the stent graft covered the aorta. In the hemorrhagic shock model (shock index ≥ 1.0), esophageal mucosal blood flow showed a remarkable change from baseline in the upper esophagus (Th1-Th3), where the stent graft did not cover the aorta (20.8 ± 9.8 ml/min/100 g vs. 12.9 ± 8.6 ml/min/100 g, P < 0.01); however, it returned to the baseline value within a 30-min period. Mucosal blood flow remained stable in the esophagus, where the stent graft did not cover the aorta. After elevating the mean blood pressure to > 70 mmHg with continuous intravenous noradrenaline infusion, esophageal mucosal blood flow increased significantly in both regions; however, the reaction was different between the two regions. Our newly developed laser Doppler flowmeter could measure real-time esophageal mucosal blood flow changes in various clinical situations during thoracic stent graft implantation in a swine model. Hence, this device can be applied in many medical fields by downsizing it.

Association of Shock Indices with Peri-Intubation Hypotension and Other Outcomes: A Sub-Study of the KEEP PACE Trial

BACKGROUND

Based on current evidence, there appears to be an association between peri-intubation hypotension and patient morbidity and mortality. Studies have identified shock indices as possible pre-intubation risk factors for peri-intubation hypotension. Thus, we sought to evaluate the association between shock index (SI), modified shock index (MSI), and diastolic shock index (DSI) and peri-intubation hypotension along with other outcomes.

METHODS

The present study is a sub-study of a randomized controlled trial involving critically ill patients undergoing intubation. We defined peri-intubation hypotension as a decrease in mean arterial pressure <65 mm Hg and/or a reduction of 40% from baseline; or the initiation of, or increase in infusion dosage of, any vasopressor medication (bolus or infusion) during the 30-min period following intubation. SI, MSI, and DSI were analyzed as continuous variables and categorically using pre-established cut-offs. We also explored the effect of age on shock indices.

RESULTS

A total of 151 patients were included in the analysis. Mean pre-intubation SI was 1.0  ±  0.3, MSI 1.5  ±  0.5, and DSI 1.9  ±  0.7. Increasing SI, MSI, and DSI were significantly associated with peri-intubation hypotension (OR [95% CI] per 0.1 increase  =  1.16 [1.04, 1.30], P  =  .009 for SI; 1.14 [1.05, 1.24], P  =  .003 for MSI; and 1.11 [1.04, 1.19], P  =  .003 for DSI). The area under the ROC curves did not differ across shock indices (0.66 vs 0.67 vs 0.69 for SI, MSI, and DSI respectively; P  =  .586). Increasing SI, MSI, and DSI were significantly associated with worse sequential organ failure assessment (SOFA) score (spearman rank correlation: r  =  0.30, r  =  0.40, and r  =  0.45 for SI, MSI, and DSI, respectively, all P < .001) but not with other outcomes. There was no significant impact when incorporating age.

CONCLUSIONS

Increasing SI, MSI, and DSI were all significantly associated with peri-intubation hypotension and worse SOFA scores but not with other outcomes. Shock indices remain a useful bedside tool to assess the potential likelihood of peri-intubation hypotension.

TRIAL REGISTRATION

ClinicalTrials.gov identifier - NCT02105415.

Association between the shock index on admission and in-hospital mortality in the cardiac intensive care unit

BACKGROUND

An elevated shock index (SI) predicts worse outcomes in multiple clinical arenas. We aimed to determine whether the SI can aid in mortality risk stratification in unselected cardiac intensive care unit patients.

METHODS

We included admissions to the Mayo Clinic from 2007 to 2015 and stratified them based on admission SI. The primary outcome was in-hospital mortality, and predictors of in-hospital mortality were analyzed using multivariable logistic regression.

RESULTS

We included 9,939 unique cardiac intensive care unit patients with available data for SI. Patients were grouped by SI as follows: < 0.6, 3,973 (40%); 0.6-0.99, 4,810 (48%); and ≥ 1.0, 1,156 (12%). After multivariable adjustment, both heart rate (adjusted OR 1.06 per 10 beats per minute higher; CI 1.02-1.10; p-value 0.005) and systolic blood pressure (adjusted OR 0.94 per 10 mmHg higher; CI 0.90-0.97; p-value < 0.001) remained associated with higher in-hospital mortality. As SI increased there was an incremental increase in in-hospital mortality (adjusted OR 1.07 per 0.1 beats per minute/mmHg higher, CI 1.04-1.10, p-Value < 0.001). A higher SI was associated with increased mortality across all examined admission diagnoses.

CONCLUSION

The SI is a simple and universally available bedside marker that can be used at the time of admission to predict in-hospital mortality in cardiac intensive care unit patients.

Predicting time-to-intubation after critical care admission using machine learning and cured fraction information

Intubation for mechanical ventilation (MV) is one of the most common high-risk procedures performed in Intensive Care Units (ICUs). Early prediction of intubation may have a positive impact by providing timely alerts to clinicians and consequently avoiding high-risk late intubations. In this work, we propose a new machine learning method to predict the time to intubation during the first five days of ICU admission, based on the concept of cure survival models. Our approach combines classification and survival analysis, to effectively accommodate the fraction of patients not at risk of intubation, and provide a better estimate of time to intubation, for patients at risk. We tested our approach and compared it to other predictive models on a dataset collected from a secondary care hospital (AZ Groeninge, Kortrijk, Belgium) from 2015 to 2021, consisting of 3425 ICU stays. Furthermore, we utilised SHAP for feature importance analysis, extracting key insights into the relative significance of variables such as vital signs, blood gases, and patient characteristics in predicting intubation in ICU settings. The results corroborate that our approach improves the prediction of time to intubation in critically ill patients, by using routinely collected data within the first hours of admission in the ICU. Early warning of the need for intubation may be used to help clinicians predict the risk of intubation and rank patients according to their expected time to intubation.

Is the shock index correlated with blood loss? An experimental study on a controlled hemorrhagic shock model in piglets

INTRODUCTION

The quantification of blood loss in a severe trauma patient allows prognostic quantification and the engagement of adapted therapeutic means. The Advanced Trauma Life Support classification of hemorrhagic shock, based in part on hemodynamic parameters, could be improved. The search for reproducible and non-invasive parameters closely correlated with blood depletion is a necessity. An experimental model of controlled hemorrhagic shock allowed us to obtain hemodynamic and echocardiographic measurements during controlled blood spoliation. The primary aim was to demonstrate the correlation between the Shock Index (SI) and blood depletion volume (BDV) during the hemorrhagic phase of an experimental model of controlled hemorrhagic shock in piglets. The secondary aim was to study the correlations between blood pressure (BP) values and BDV, SI and cardiac output (CO), and pulse pressure (PP) and stroke volume during the same phase.

METHODS

We analyzed data from 66 anesthetized and ventilated piglets that underwent blood spoliation at 2 mL.kg-1.min-1 until a mean arterial pressure (MAP) of 40 mmHg was achieved. During this bleeding phase, hemodynamic and echocardiographic measurements were performed regularly.

RESULTS

The correlation coefficient between the SI and BDV was 0.70 (CI 95%, [0.64; 0.75]; p < 0.01), whereas between MAP and BDV, the correlation coefficient was -0.47 (CI 95%, [-0.55; -0.38]; p < 0.01). Correlation coefficient between SI and CO and between PP and stroke volume were - 0.45 (CI 95%, [-0.53; -0.37], p < 0.01) and 0.62 (CI 95%, [0.56; 0.67]; p < 0.01), respectively.

CONCLUSIONS

In a controlled hemorrhagic shock model in piglets, the correlation between SI and BDV seemed strong.

Clinical factors predicting return emergency department visits in chemotherapy-induced febrile neutropenia patients

BACKGROUND

Although chemotherapy-induced febrile neutropenia (FN) is the most common and life-threatening oncologic emergency, the characteristics and outcomes associated with return visits to the emergency department (ED) in these patients are uncertain. Hence, we aimed to investigate the predictive factors and clinical outcomes of chemotherapy-induced FN patients returning to the ED.

METHOD

This single-center, retrospective observational study spanning 14 years included chemotherapy-induced FN patients who visited the ED and were discharged. The primary outcome was a return visit to the ED within five days. We conducted logistic regression analyses to evaluate the factors influencing ED return visit.

RESULTS

This study included 1318 FN patients, 154 (12.1%) of whom revisited the ED within five days. Patients (53.3%) revisited the ED owing to persistent fever (56.5%), with no intensive care unit admission and only one mortality case who was discharged hopelessly. Multivariable analysis revealed that shock index >0.9 (odds ratio [OR]: 1.45, 95% confidence interval [CI], 1.01-2.10), thrombocytopenia (<100 × 10³/uL) (OR: 1.64, 95% CI, 1.11-2.42), and lactic acid level > 2 mmol/L (OR: 1.51, 95% CI, 0.99-2.25) were associated with an increased risk of a return visit to the ED, whereas being transferred into the ED from other hospitals (OR: 0.08; 95% CI, 0.005-0.38) was associated with a decreased risk of a return visit to the ED.

CONCLUSION

High shock index, lactic acid, thrombocytopenia, and ED arrival type can predict return visits to the ED in chemotherapy-induced FN patients.

Effects of growth trajectory of shock index within 24 h on the prognosis of patients with sepsis

Background

Sepsis is a serious disease with high clinical morbidity and mortality. Despite the tremendous advances in medicine and nursing, treatment of sepsis remains a huge challenge. Our purpose was to explore the effects of shock index (SI) trajectory changes on the prognosis of patients within 24 h after the diagnosis of sepsis.

Methods

This study was based on Medical Information Mart for Intensive Care IV (MIMIC- IV). The effects of SI on the prognosis of patients with sepsis were investigated using C-index and restricted cubic spline (RCS). The trajectory of SI in 24 h after sepsis diagnosis was classified by latent growth mixture modeling (LGMM). Cox proportional hazard model, double robust analysis, and subgroup analysis were conducted to investigate the influence of SI trajectory on in-hospital death and secondary outcomes.

Results

A total of 19,869 patients were eventually enrolled in this study. C-index showed that SI had a prognostic value independent of Sequential Organ Failure Assessment for patients with sepsis. Moreover, the results of RCS showed that SI was a prognostic risk factor. LGMM divided SI trajectory into seven classes, and patients with sepsis in different classes had notable differences in prognosis. Compared with the SI continuously at a low level of 0.6, the SI continued to be at a level higher than 1.0, and the patients in the class whose initial SI was at a high level of 1.2 and then declined had a worse prognosis. Furthermore, the trajectory of SI had a higher prognostic value than the initial SI.

Conclusion

Both initial SI and trajectory of SI were found to be independent factors that affect the prognosis of patients with sepsis. Therefore, in clinical treatment, we should closely monitor the basic vital signs of patients and arrive at appropriate clinical decisions on basis of their change trajectory.

Association between Shock Index and Emergency Department Cardiac Arrest

Background

In the emergency department (ED), early identification of patients at risk of cardiac arrest is paramount, especially in the context of overcrowding. The shock index (SI) is defined as the ratio of heart rate to systolic blood pressure. It is a tool used for predicting the prognosis of critically ill and injured patients. In this study, we have discussed the relationship between SI and cardiac arrest in the ED.

Methods

Patients who experienced cardiac arrest in the ED were classified into two groups, SI ≥ 0.9 and < 0.9, according to their triage vital signs. The association between SI ≥ 0.9 and in-hospital mortality was analyzed in five different etiologies of cardiac arrest, including hypoxia, cardiac cause, bleeding, sepsis, and other metabolic problems.

Results

In total, 3,313 patients experienced cardiac arrest in the ED. Among them, 1,909 (57.6%) had a SI of ≥0.9. The incidence of SI ≥ 0.9 in the five etiologies was 43.5% (hypoxia), 58.1% (cardiac cause), 56.1% (bleeding), 58.0% (sepsis), and 65.5% (other metabolic problems). SI was associated with in-hospital mortality (adjusted odds ratio (aOR), 1.6; 95% confidence interval (CI), 1.5–1.8). The aOR (CI) in the five etiologies was 1.3 (1.1–1.6) for hypoxia, 1.8 (1.6–2.1) for cardiac cause, 1.3 (0.98–1.7) for bleeding, 1.3 (1.03–1.6) for sepsis, and 1.9 (1.5–2.1) for other metabolic problems.

Conclusion

More than half of the patients who experienced cardiac arrest in the ED had a SI ≥ 0.9. The SI was also associated with in-hospital mortality after cardiac arrest in the ED. SI maybe used as a screening tool to identify patients at risk of cardiac arrest in the ED and a predictor of mortality in those experiencing cardiac arrest in the ED.

Shock Index, Pediatric Age-Adjusted Predicts Morbidity and Mortality in Children Admitted to the Intensive Care Unit

Background: The shock index, pediatric age-adjusted (SIPA), defined as the maximum normal heart rate divided by the minimum normal systolic blood pressure by age, can help predict the risk of morbidity and mortality after pediatric trauma. This study investigated whether the SIPA can be used as an early index of prognosis for non-traumatic children visiting the pediatric emergency department (ED) and were directly admitted to the intensive care unit (ICU). We hypothesized that an increase in SIPA values in the first 24 h of ICU admission would correlate with mortality and adverse outcomes. Methods: This multicenter retrospective study enrolled non-traumatic patients aged 1-17 years who presented to the pediatric ED and were directly admitted to the ICU from January 1, 2016, to December 31, 2018, in Taiwan. The SIPA value was calculated at the time of arrival at the ED and 24 h after ICU admission. Cutoffs included SIPA values >1.2 (patient age: 1-6), >1.0 (patient age: 7-12), and >0.9 (patient age: 12-17). The utility of the SIPA and the trends in the SIPA during the first 24 h of ICU admission were analyzed to predict outcomes. Results: In total, 1,732 patients were included. Of these, 1,050 (60.6%) were under 6 years old, and the median Pediatric Risk of Mortality score was 7 (5-10). In total, 4.7% of the patients died, 12.9% received mechanical ventilator (MV) support, and 11.1% received inotropic support. The SIPA value at 24 h after admission was associated with increased mortality [odds ratio (OR): 4.366, 95% confidence interval (CI): 2.392-7.969, p < 0.001], MV support (OR: 1.826, 95% CI: 1.322-2.521, p < 0.001), inotropic support (OR: 2.306, 95% CI: 1.599-3.326, p < 0.001), and a long hospital length of stay (HLOS) (2.903 days, 95% CI: 1.734-4.271, p < 0.001). Persistent abnormal SIPA value was associated with increased mortality (OR: 2.799, 95% CI: 1.566-5.001, p = 0.001), MV support (OR: 1.457, 95% CI: 1.015-2.092, p = 0.041), inotropic support (OR: 1.875, 95% CI: 1.287-2.833, p = 0.001), and a long HLOS (3.2 days, 95% CI: 1.9-4.6, p < 0.001). Patients with abnormal to normal SIPA values were associated with decreased mortality (OR: 0.258, 95% CI: 0.106-0.627, p = 0.003), while patients with normal to abnormal SIPA values were associated with increased mortality (OR: 3.055, 95% CI: 1.472-5.930, p = 0.002). Conclusions: In non-traumatic children admitted to the ICU from the ED, increased SIPA values at 24 h after ICU admission predicted high mortality and bad outcomes. Monitoring the trends in the SIPA could help with prognostication and optimize early management.